How many HPS 1000k lights for 4x4 tray?

I am getting different information a/f:
1.1x 1000 watt hps for 1 4x4 tray for indica 3 foot tall plant on hydro flat table
2.1x 1000 watt hps for 2 4x4 trays """""""""""""
2. 2 x 1000 watt hps for 1 4x8 tray """""""""""""""""

I am trying to buy lights and tray right now but I can't figure out how many lights I need per tray...based on 3 different opinions above. Which one is best?

the first and third option say the same thing. 1000 watts should be plenty for a four by four area. i use 600's for 3foot 6 by 3 foot 6 areas,
with very good results.it would be difficult to cover two trays without a light mover.